NBA's commish recently teased the league might consider the idea of having a hard salary cap in the future in order to have better league parity and also implied at not wanting another Cavs-Warriors IV NBA Finals series scenario to happen again.
Right now its a soft cap but with a stricter luxury tax than in MLB since its around $1 in tax for every $1 over the cap limit.
http://www.espn.com/nba/story/_/id/2...ryan-colangelo